Senior interview question
In the capstone, continuous batching with at most 8 seats gives a p90 first token of 122 ms against a 300 ms target, yet the planner marks it failing. Why, how do you fix it, and what would you measure first on the real system?
Model answer
It has no headroom. Capacity, the highest arrival rate still within 300 ms at p90, is 6 per second against a target of 9: eight seats fill as traffic grows, and requests queue. A larger batch limit buys capacity until the KV caches break the 2 GB budget.
It's simulated from measured steps, but those were measured at a 128-token context while this workload reaches 768, so it's optimistic. First real measurement: p90 TTFT and capacity under the real workload.
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